This invention relates to gas generation, and more particularly to the generation of a microaerophilic atmosphere.
It is well known that some microorganisms require an aerobic atmosphere for growth whereas other microorganisms require an anaerobic atmosphere. Still other microorganisms, however, require an atmosphere having a predetermined level of oxygen falling between aerobic and anaerobic conditions, such atmospheric conditions are referred to herein as "microaerophilic atmospheres."
The attainment of an aerobic atmosphere is relatively simple, in most cases merely requiring aeration of the culture media. Anaerobic conditions are more difficult to attain and the prior art contains many devices and processes for producing anaerobic atmospheres. U.S. Pat. No. 3,246,959, discloses an apparatus for generating such anaerobic atmospheres and U.S. Pat. No. 3,483,089 discloses anaerobic apparatus for anaerobic culturing, which includes a cold platinum catalyst. In accordance with U.S. Pat. No. 3,246,959, there is provided a package which includes, for example, a material which is capable of generating hydrogen upon being contacted with water. The interior of the package is divided into two compartments, which are in fluid flow communication with each other, with one of the compartments including the hydrogen generating material. Upon introducing water into the other compartment, there is a controlled flow of water into the compartment containing the hydrogen generating material. Such package can be employed in an anaerobic jar such as disclosed in U.S. Pat. No. 3,483,089.
U.S. patent application Ser. No. 26,337, filed Apr. 2, 1979, now U.S. Pat. No. 4,287,306, describes a further apparatus for generating anaerobic atmospheres. In accordance with this patent application, a flexible sealed package is provided with a catalyst coated onto the exterior surface of the package for use in catalyzing the reaction between oxygen outside the package, and hydrogen generated from a hydrogen generating material within the package upon introduction of water into a compartment within the package.
In general, as described hereinabove, anaerobic conditions are attained by providing a closed container, a stoichiometric excess of hydrogen produced by a hydrogen generating material and a catalyst to cause reaction of the hydrogen with all of the oxygen in the container to form water. When faced with the problem of providing a microaerophilic atmosphere, the first thought of one skilled in the art of bacterial culture would be to use anaerobic gas generating apparatus and to reduce the amount of hydrogen generating material to the stoichiometric level required to cause reaction with only that portion of the oxygen which it is desired to remove. Such simple substitution of stoichiometric quantities of hydrogen generating materials in existing anaerobic apparatus, however, has not been wholly successful.
The present invention is directed to an improvement in such gas generating devices and to the provision of a gas generating device suitable for use in applications requiring a microaerophilic atmosphere.